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' CHARLES w. H A'roN, OF LEssNEss HEATH, COUNTY KENT, AND THOMAS BOLAS,or CHISWICK, COUNTY OF MIDDLESEX, ENGLAND, ASSIGNORS TO IHLEE a HORNE,or LoNDoN, ENGLAND.

PRODUCTION OF VITRIFIED COVERIN GSON EARTHENWARE, GLASS, &c.

SPECIFICATION forming part of Letters Patent No. 254,312, dated February28 1882.' Application filed December 22, 1881. (No specimens.) Patentedin England October 31, 1881.

To all whom it may concern:

Be it known that we, CHARLES WILLIAM HEATON and THOMAS BoLAs,subjects ofthe Queen of Great Britain and Ireland, residing respectively atLessness Heath, in the county of Kent, and at Ghiswick, in the county ofMiddlescx, both in the Kingdom of GrcatBr-itain and Ireland, haveinvented new and useful Improvements in the Production of Enamel or mVitrified Govering's on Eartln-nware, Glass, Metals, Stone, and otherSuhstances,(for which we have'obtaiucd Provisional Protection in GreatBritain No. 4,762, bearingdate October 31, 1881;) and we do herebydeclare that the following is a full, clear, and exactdescrlption of theinvention, which will enable others skilled in the art to which itappertains to make and use the same. According to ourinveution we mixwith one aoI-or'more of the materials ordinarily used, or

- \vhich may be used, in the production of vitrifled enamels, aphosphorescent; substance or substances, such as will, after exposure tolight, remain luminous for some hours, and we put as some of thismixture on the object to be enameled, after which we expose the saidobject to a heat sufiici'ent in dcgrc to melt, or partially melt, themixture. The phosphorescent substance employed 0 may be luminous powder,such as is usedin the manufacture of luminous paint, according to theinvention for which British Letters Pat out No. 4,152, dated. November7, 1877, were granted to the late \V. H. Balmaim'or such as 5 can bepurchased from W. Puzey,.ot" 5 Aldermanbury Postern, in the city ofLondon, or from his agents; but we donot confine ourselves to theseparticular phosphorescent substances, but use any suitablephosphorescent 4o substance, restricting ourselves, howcver,vto thosewhose luminosity is of a useful duration -that is, such as are avail-.1ble for thepurposes of practical illumination for several hours afterexposure to light.

By one or more of the materials ordinarily used, or which may be used,inthe production of vitrified enamels, we mean any of the ordi naryfusible materials or fluxes usedsin-gly, or

admixed by potters and enamelers for the pro- 5o duction of glazesorenamels; but all mixtures 'stantially as described.

containing lead, antimony, iron-, tin, and other substances which formdark-colored conr poundswith sulphur must be avoided, unless such metalsor other substances are only pres. ent in a very small proportion. \Veprefer to use a mixture of the phosphorescent-. powder sold by\V..Puzey, with two.- thirds of its weight of pure and finely-powderedfluoride of calcium, and aboutone-fitth of its weight of borate ofcalcium; but we do not restrict ourselves to these proportions or tothese substances. The above materials we mix in the form of powder,which powder is either laid or spread on the'article to beornameuted,-after which the heat necessary for fusion is applied; or itmay be mingled with watenso' as to form a. kind of cream, into which thearticles may be dipped or with which they may be painted.

When dry they are fired, as in the previous case.

What we claim isp 1. In the manufacture of enamel or vitrifiedcoveringfor earthenware or other substances, the combination therewithof phosphorescent powder of the kind above referred to, so as to 75 makesaid enamel available for the purposes of practical illuminationfor-several hours after exposure to light, substantially as described.

2. The process of manufacturing or produc ing luminous enamel orvvitrified coveringon 8o earthenware and other substances, which consistsin combining with the other ingredients constituting said enamels, asabove set forth, phosphorescent powder having the property ,of remainingluminous for several hours after 8 5 exposure to light, and afterwardsubjecting themixturc to heat 'of such intensity as to melt, orpartially melt,'the said mixture, substantially as described.

3. "As a new article of manufacture, cnamehgo rendered luminous byaddition of phosphorescent powder of the kind above specified, sub-(JHARLES WILLIAM HEATON. THOMAS BOLAS. I Witnesses:

W. LLOYD WISE, Patent Age-nt,Lo-ndon.

J. J. Bsouonm,

7 'Whitchtdlllace, S. W.

